The Human Fetal Tissue and Primary Neuroglial Cell Culture Core is designed to provide human fetal tissues and specific primary human fetal neuroglial and neuronal cell populations to investigators in the projects associated with this Program Project. The Specific Aims of the Human Fetal Tissue and Primary Neuroglial Cell Culture Core are to: (1) generate highly purified, characterized populations of human fetal astrocytes of defined gestational age for experiments relevant to chemokine receptor and HIV-1 susceptibility analyses (utilized by investigators in Project 3 and 5); 2) generate highly purified, characterized populations of human fetal microglial cells of defined gestational age for experiments directed toward chemokine receptor and HIV-1 susceptibility analyses; (3) generate highly purified, characterized populations of human fetal CNS and peripheral sensory neurons of defined gestational age for experiments involving chemokine receptor and neurotoxicity analyses; and 4) provide segments of human fetal long bone for construction of SCID mice carrying xenografts of the human immune system [SCID-hu BTL (Bone- Thy/liv-Lymph node) mouse or experiments relevant to analyses of cellular phenotype and HIV-1 susceptibility of human immune cell components subsequent to cellular migration into the mouse CNS (utilized by investigators in Project 1). The Human Fetal Tissue and Primary Neuroglial Cell Culture Core is located in the Department of Microbiology and Immunology at the Penn State College of Medicine in Hershey, Pennsylvania, located 90 miles est of Philadelphia and the University of Pennsylvania campus. Dr. Brain Wigdahl, Director of this Core Project, has been associated with this Program Project since its inception now more than 10 years ago. As detailed in Research Design & Methods, human fetal tissues and primary CNS cell populations will be provided to program Project investigators on a weekly basis. As outlined, human fetal tissues and cells will be delivered from Harrisburg/Hershey to Philadelphia within 4 hours of the surgical procedure by courier.